With the advance of technology, gesture recognition is playing a very important, role in, virtual reality applications and the control of electronic devices. There are already many studies focus on capturing and interpreting gestures of a user's body and then using the interpretation as inputs of a virtual reality application for enabling the user to interact with characters in the virtual reality ambient. One such study is a hand-free navigation system disclosed in U.S. Pat. No. 6,009,210, entitled “HAND-FREE INTERFACE TO A VIRTUAL REALITY ENVIRONMENT USING HEAD TRACKING”, which uses a camera to catch images of a user's body and then the images are analyzed and interpreted so as to use the interpretation as inputs of an interactive virtual reality application. However, the cost of such system can be very expensive that it is not acceptable for general consumers and thus is not yet popularized and realized. Another such study is a hand-held communication device disclosed in U.S. Pat. No. 4,905,001, entitled “HAND-HELD FINGER MOVEMENT ACTUATED COMMUNICATION DEVICES AND SYSTEMS EMPLYING SUCH DEVICES”, which can be a finger cot or wriest strap having a plurality of micro-switches that are subjected to be pressed by nature hand movements. By the on/off of those micro-switches activated by the pressing caused by hand movements, signals corresponding to the pressed micro-switches are sent to trigger responses of certain electronic devices such that those electronic devices are enabled to respond to natural hand movements. However, the aforesaid device can only be worn in the proximity of joints of a hand that it is failed to describe a complete moving gesture of the hand.
As the mature of MEM process, the size of micro inertial sensing component is greatly reduced. Therefore, it is common to use micro inertial sensing components to detect motions and kinematic poses generated by humans. One such apparatus is disclosed in U.S. Pat. No. 5,617,515, entitled “METHOD AND APPARATUS FOR CONTROLLING AND PROGRAMMING A ROBOT OR OTHER MOVEABLE OBJECT”, in which inertial components are arranged inside an apparatus having a handle. As the handle is held in a hand of a user to enable the apparatus to rotate/move following the movement of the hand, a robotic arm remotely coupled to the apparatus is enabled to rotate/move following the orientation and translation detected by the inertial components.
In addition, another such apparatus is disclosed in U.S. Pat. No. 6,072,467, entitled “CONTINUOUSLY VARIABLE CONTROL OF ANIMATED ON-SCREEN CHARACTERS”, which is an egg-shaped hand-held device having, a natural orientation when grasped by hand. As the egg-shaped device is moved or wave around by an individual in a series of motions, accelerations will be sensed by the accelerometers embedded in the device that are used to control on-screen animated characters presented by a computer-driven display. Moreover, the acceleration waveforms of a series of hand gestures are identifiable as a signal for generating a motion control of an animated character by correlating the template of histogram of such waveforms to the motion control, whereas the correlation between the templates and the motion controls is considered to be a predefined language that can be specified by an individual through a training session. For instance, movement of the egg-shaped quickly to the right and then to the left indicates to the system that a character right turn is required; a left turn is illustrated when egg-shaped device is moved quickly to the left and then to the right; an increase in speed is illustrated as a quick movement of egg-shaped device upwards, followed by a downward movement; and a decrease in speed is indicated oppositely. However, by using the aforesaid hand-held device to remotely control an on-screen animated characters, only hand gestures of an individual can be detected thereby while movements of other body parts, e.g. fingers, legs, etc., of the individual are not, and further that, a user must go through a training session before one can use the hand-held device to control the animated character at will as the correlation between the templates and the motion controls is considered to be a predefined language that required to be specified by the individual. Therefore, the aforesaid hand-held device is short that: the degree-of-freedom of the device is not sufficient and the learning session might be difficult for ordinary user since the language may become very complicated as the motion control increases.
Another study of gesture recognition focus on developing a sensing device that can be worn or adhere to any part of a user's body so as to describe a complete body movement of the user. One such device is disclosed in U.S. Pat. No. 6,747,632, entitled “WIRELESS CONTROL DEVICE”, which can be a housing worn on a user. The housing has several light emitting diodes (“LEDs”) operating in the infrared range, project well-defined beams of energy over a limited solid angle generally parallel to the palm of the user's hand. The solid angle of the beams is preferably limited such that the illuminated regions will not overlap at a distance from housing 22 that is closer than the fingertips of the user. Thus, movement of the user's hand, such as movement of a finger in a motion similar to pressing a key on a keyboard, will cause the tip of the user's finger to be illuminated by a beam. This illumination is reflected from the user's fingertip and detected by a detector, also on the housing. Thus, by correlation of reflected beams with emitted beams, the placement of any finger or other object can be not only detected but also differentiated from any other location, and an appropriate coded signal can be sent from the housing to an electronic device controlled by the housing. In addition, except for those LEDs, there may be several inertial sensors there's no detailed description disclosed in the aforesaid U.S. patent referring about the operation principle of the inertial sensors.
One more study about human gesture recognition is disclosed in U.S. Pat. No. 6,681,031, entitled “GESTURE-CONTROLLED INTERFACES FOR SELF-SERVICE MACHINES AND OTHER APPLICATIONS”, as shown in FIG. 1, which details methods for gesture recognition, as well as the overall architecture for using gesture recognition to control of devices. There is a one-to-one relation between a gesture and a command message corresponding thereto. During the gesture making process, a video image is captured for producing image data along with timing information. As the image data is produced, a feature-tracking algorithm is implemented which outputs position and time information, whereas the position information is processed by static and dynamic gesture recognition algorithms. When the gesture is recognized, a command message corresponding to that gesture type is sent to the device to be controlled, which then performs the appropriate response. However, in the aforesaid U.S. patent, a video image is still required for gesture recognition so that such gesture recognition apparatus can not be portable, convenient-to-use, and inexpensive.
Therefore, it is in great need to have a motion recognition system and method for controlling electronic devices to interact with a user, which is free from the shortcomings of prior art.